Jon Boy's thread reminded me of all the tongue twisters I'd learnt in my acting class. With a little practice, I got pretty good at them:
Think the Peter Piper ditty, only thusly:
Billy Button bought a bunch of beautiful bananas (a bunch of beautiful bananas Billy Button bought, etc.)
Danny Davis did a dastardly deed...
Mimi Miller made some marvelous marmalaide...
Cathryn Crosby kept a cuddly kitten in her closet...
A few more that I liked:
He thrusts his fists against the posts, and still insists he sees the ghosts.
Will you wait for Willie and Winnie? (this was done seven times in one breath: WILL you wait for willie and winnie will YOU wait for willie and winnie will you WAIT for willie and winnie...etc.)
This one I never could get the hang of: Unique New York.
There were more little two word ones that my poor tongue could not do, but I cannot remember them.